Game systems have been developed and implemented in the art, to enable a player to use a position indication device such as a handgun-shaped controller to shoot at a target object. In such a game system, a player 302 holds a handgun-shaped controller 300, aims at a target object displayed on a screen 312 of a display device 310, and pulls a trigger 304. When that happens, a position 314 indicated by the handgun-shaped controller 300 is detected optically by using means such as an optical sensor within the handgun-shaped controller 300. If the indicated position 314 of the handgun-shaped controller 300 matches the position of the target object that is displayed on the screen 312, a hit is determined; if it does not match, a miss is determined. Prior-art techniques for implementing such a handgun-shaped controller and game system are disclosed in Japanese Patent Application Laid-Open No. 10-118338, by way of example.
The intensity of light output from a display device such as a television is extremely low, on the order of 300 lux. For that reason, an extremely sensitive optical sensor is used within the handgun-shaped controller 300.
The intensity of external light (environmental light) in the real world, however, is extremely strong and can be on the order or ten to twenty thousand lux outdoors, by way of example. Therefore, if the game system of FIG. 1 is taken outside with the objective of entertaining a home party or the like, the optical sensor within the handgun-shaped controller 300 is likely to react to the external light, not the light from the display device 312, which will raise the problem of erroneous operation.
One method that could be considered for solving such a problem is to form the casing (indicator body) of the handgun-shaped controller 300 of a material that is highly light-proof. Use of such a method ensures that external light is excluded by the casing made of the highly light-proof material, making it possible to solve the problem of the optical sensor reacting to external light.
If this method is used, however, the material of the casing of the handgun-shaped controller 300 is limited to materials that are highly light-proof, which restricts the color of the casing. It is therefore difficult to use organic colorants or the like, and it is thus substantially impossible to utilize any of the “skeleton” (translucent) colors and pastel colors that are currently fashionable, as the color of the casing. This restricts the degree of freedom of design of the handgun-shaped controller, with the result that the product value of the handgun-shaped controller is reduced.